Okay, let's break down the best way to handle wiring your mini-split, focusing on code compliance, protection, and aesthetics. I will provide general guidance. It is critical to consult your local electrical codes and a qualified electrician for final approval and installation. Incorrect wiring can be dangerous and violate code.

Understanding the Situation Ductstrip Wire

This is generally intended to run through ductwork and not for use in outside conduits. Please verify that the wire that was pulled is indeed the correct size and type for its new application and that it can be placed in conduit.

Sleeving in Non-Metallic Liquid Tight (Liquidtight Flexible Nonmetallic Conduit - LFNC)

This is an excellent approach for protecting the wiring from the elements and potential physical damage.

Planning the Run1. Assess the Wire



Wire Type and Size

Crucially, verify that the wire is the correct gauge (thickness) and type (e.g., THHN/THWN) suitable for both the mini-split's voltage, current (amps), and the environment (wet location rated if exposed to weather).

This is the most important step. You cannot safely use wire that's not rated for this specific outdoor application. The wire needs to be rated for exposure to sunlight. Number of Conductors

Ensure you have the correct number of conductors (wires) for the mini-split's power, control, and communication needs. Typically, you'll need wires for power (L1, L2/Neutral, and Ground), plus one or more for control/communication.

If the wire is not correct

It will need to be replaced before proceeding with the install2.

Route

Plan the most direct, protected, and aesthetically pleasing route for the conduit run from the house to the outdoor unit. Avoid areas where it's likely to be damaged (e.g., walkways, lawnmower paths).3.

Conduit Size

Choose the appropriate size of LFNC to accommodate the wires. A common size is 3/4" or 1", but this depends on the number and gauge of the wires. Use a conduit fill calculator (easily found online) to ensure you don't exceed the maximum fill capacity. Overfilling conduit can make pulling wires extremely difficult and can damage the wire insulation.

Transition at the House Exit

Here's a good method for transitioning from inside the house to the outdoor LFNC run:1. Exit Point Preparation



Drill Hole

Carefully drill a hole through the wall where you want the wiring to exit. Be mindful of what's behind the wall (wiring, plumbing, etc.). The hole should be large enough for the conduit connector and the wire.

Sealant

Apply weatherproof sealant (e.g., silicone caulk) around the hole to prevent water and air infiltration.2.

Using a Non-Metallic Box



Non-Metallic Bell Box

A weatherproof non-metallic bell box is a solid choice.

Mounting

Mount the bell box securely to the exterior wall using appropriate screws for the wall material (e.g., wood screws for wood siding, masonry screws for brick/concrete).

Wiring Inside

Inside the bell box, make your wire connections. Use appropriately sized wire connectors (wire nuts) and ensure all connections are tight.

Alternatively, a Weatherproof LB Fitting

An LB fitting provides a 90-degree bend and allows for easier wire pulling. These are available in non-metallic versions.3.

Attaching the Conduit to the Box/Fitting



Liquidtight Connector

Use a liquidtight connector specifically designed for LFNC to connect the conduit to the bell box or LB fitting. These connectors have a compression fitting that seals the conduit to prevent water entry.

Installation

Insert the conduit into the connector, tighten the compression nut securely, and ensure the connector is properly seated in the bell box knockout or LB fitting threads.4.

The "Chase Nipple" Issue



Metallic Chase Nipple for grounding

Non-metallic chase nipples aren't typically used. The back of the bell box, where it contacts the house's exterior, is generally sufficient for a weatherproof seal when properly mounted. If you are using metallic bell boxes you would need a grounding bushing and possibly a bonding jumper.

Wiring the Outdoor Unit1. Run the Conduit

Carefully run the LFNC from the bell box/LB fitting to the outdoor unit. Secure the conduit to the wall or other surfaces using conduit clamps or straps. Space the clamps appropriately (check your local code for specific requirements).2.

Entry into the Outdoor Unit



Knockout

Most outdoor units have a knockout specifically for wiring entry.

Liquidtight Connector

Use another liquidtight connector to connect the LFNC to the knockout on the outdoor unit.

Sealing

Ensure a tight seal to prevent water from entering the unit.3.

Wiring Connections



Follow Manufacturer's Instructions

Carefully follow the mini-split manufacturer's wiring diagram and instructions.

Secure Connections

Use appropriate wire connectors and ensure all connections are tight and secure.

Grounding

Properly ground the outdoor unit according to the manufacturer's instructions and local electrical codes.

Important Considerations and Warnings Local Electrical Codes

Always consult your local electrical codes and building regulations. These codes vary by location and are designed to ensure safety.

Permits

Check if you need an electrical permit for this type of work.

Qualified Electrician

If you're not comfortable working with electrical wiring, hire a qualified electrician. Electrical work can be dangerous and should only be performed by someone with the necessary knowledge and experience.

Turn Off Power

Always turn off the power to the circuit at the breaker before working on any wiring. Use a non-contact voltage tester to verify that the power is off.

Wire Fill

Never overfill the conduit. This makes pulling wires difficult and can damage the insulation.

Sunlight Resistance

If the LFNC will be exposed to direct sunlight, make sure it's rated for sunlight resistance (look for the "sunlight resistant" marking on the conduit).

Sealing

Properly seal all connections and penetrations to prevent water from entering the electrical system.

GFCI Protection

Consider whether GFCI (Ground Fault Circuit Interrupter) protection is required for this circuit, especially if it's an outdoor circuit.*

Testing

After completing the wiring, test the circuit with a multimeter to ensure proper voltage and continuity.

In summary: Using LFNC is a good way to protect the wiring. A non-metallic bell box (or LB fitting) at the house exit, along with liquidtight connectors, will provide a weatherproof and code-compliant installation. But make absolutely sure the wire itself is rated and sized appropriately for the application. If you're unsure, consult a qualified electrician. Flag for review